Titanyl phthalocyanin crystal, method for preparing the same and electrophotographic photoconductor

ABSTRACT

According to the present invention, a titanyl phthalocyanin crystal excellent in storage stability in organic solvents, a method for preparing the same and an electrophotographic photoconductor using the same are provided. In the titanyl phthalocyanin crystal, the method for preparing such a titanyl phthalocyanin crystal and the electrophotographic photoconductor using the same, the titanyl phthalocyanin crystal is characterized by having the maximum peak at a Bragg angle 2θ±0.2°=27.2° in a CuKα characteristic X-ray diffraction spectrum and one peak within the range of 270 to 400° C. other than a peak accompanied by the vaporization of adsorbed water in a differential scanning calorimetric analysis.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a titanyl phthalocyanin crystalprepared from a titanyl phthalocyanin compound, the method for preparingthe same and an electrophotographic photoconductor using the same.Particularly, the present invention relates to a titanyl phthalocyanincrystal excellent in the storage stability in organic solvents, themethod for preparing the same and an electrophotographic photoconductorusing the same.

2. Related Art

Generally, organic photoconductors have been frequently and recentlyused in electrophotographic photoconductors applied inelectrophotographic devices such as a copy machine and a laser printer,etc. upon such requirements as low cost and low environment pollutingproperty, etc. Phthalocyanin pigments that are sensitive to a light ofinfrared to near-infrared wavelengths irradiated from a semiconductorlaser or an infrared LED, etc. have been widely used ascharge-generating agent used in such organic photoconductors.

It has been known that metal-free phthalocyanin compounds, copperphthalocyanin compounds, titanyl phthalocyanin compounds, etc. exist insuch phthalocyanin pigments depending on a chemical structure thereof,and various crystal types can be obtained due to different preparationconditions for each phthalocyanin compound.

Thus, it has been known that when a photoconductor using a titanylphthalocyanin with a Y-type crystal structure as a charge-generatingagent is constituted in the existence of many types of phthalocyanincompound crystals having different crystal types, electriccharacteristics in the photoconductor is improved as compared with acase of using tithanylphthalocyanines of other crystal types.

For example, there has been disclosed a method for preparing a Y-typecrystal prepared by reacting a titanium compound and an organic compoundthat is a titanyl phthalocyanin having the maximum peak at a Bragg angle(2θ±0.2°)=27.3° for a CuKα line in an X-ray diffraction spectrum and canform a phthalocyanin ring under conditions of 130° C. and about 4 hrs indialkyl-aminoalcohol added with urea or ammonia (e.g., Patent document1).

There has also been disclosed a method for preparing a titaniumphthalocyanin compound of Y-type crystal prepared by directly reactingo-phthalonitrile and titanium tetrabutoxide without using a ureacompound under conditions of 215° C. and about 2 hrs (e.g., Patentdocuments 2 and 3).

More specifically, there has been disclosed a method for preparing atitanyl phthalocyanin crystal having a peak within a predetermined rangein the CuKα characteristic X-ray diffraction spectrum and no peak withinthe range of 50 to 400° C. in the differential scanning calorimetricanalysis.

[Patent document 1] JPH8-176456A (examples)

[Patent document 2] JP3463032 (claims)

[Patent document 3] JP2004-145284A (claims)

SUMMARY OF THE INVENTION Problems to be Solved

However, according to Patent document 1, there has been found theproblem that the prepared titanyl phthalocyanin crystal having a Y-typestructure had a tendency to cause crystal transition to a β-type orα-type crystal in a coating solution for a photosensitive layer.Therefore, there has been found the problem that the coating solutionfor the photosensitive layer is insufficient in storage stability, andthereby a photosensitive layer having good electric characteristicscannot be formed.

On the other hand, when a titanyl phthalocyanin crystal described inPatent document 2 or Patent document 3 was used, the crystal transitionfrom the Y-type crystal in the coating solution for the photosensitivelayer to a β-type crystal poor in sensitivity characteristic could beinhibited, but there found such a case that an image forming deviceusing a photoconductor with a titanyl Phthalo-cyanin crystal describedin Patent document 2 or Patent document 3 caused fogging and did notgive a good image under a high temperature condition and a high humiditycondition.

Therefore, as a result of intensive investigation for solvingabove-mentioned problems, present inventors discovered that the storagestability of a titanyl phthalocyanin crystal in organic solvents wasenhanced and a good image was simultaneously obtained by controlling thecrystal so as to have a peak at a prescribed Bragg angle in the CuKαcharacteristic X-ray diffraction spectrum, and at the same time, haveone peak within a predetermined temperature range in the differentialscanning calorimetric analysis.

That is, the object of present invention is to provide a titanylphthalocyanin crystal excellent in storage stability in organicsolvents, a method for preparing such a titanyl phthalocyanin crystaland an electrophotographic photoconductor using the same.

The Means for Solving the Problems

The present invention enables to provide a titanyl phthalocyanin crystalcharacterized by having the maximum peak at a Bragg angle 2θ±0.2°=27.2°in a CuKα characteristic X-ray diffraction spectrum and one peak withinthe range of 270 to 400° C. other than a peak accompanied by thevaporization of adsorbed water in a differential scanning calorimetricanalysis to solve the above-mentioned problems.

That is, if the crystal is the titanyl phthalocyanin crystal having suchan optical characteristic and thermal characteristic, it may effectivelyinhibit the crystal transition to the α-type crystal or β-type crystaleven if it is immersed in an organic solvent for a long time, e.g., 7days or longer. Accordingly, the present invention enables to obtain acoating solution for a photosensitive layer more excellent in storagestability and stably constitute an electrophotographic photoreceptorexcellent in electric characteristics and image characteristics by usingthe same.

It is preferable that the titanyl phthalocyanin crystal of presentinvention has no peak at a Bragg angle 2θ±0.2°=26.2° in the CuKαcharacteristic X-ray diffraction spectrum when the crystal is prepared.

Due to such a composition, the transition of titanyl phthalocyanincrystal to the β-type may be further controlled for a long time and thestorage stability of titanyl phthalocyanin crystal in organic solventsmay be further improved.

It is preferable that the titanyl phthalocyanin crystal of presentinvention recovered after being immersed for 7 days in an organicsolvent has at least the maximum peak at a Bragg angle 2θ±0.2°=27.2° andno peak at 26.2° in the CuKα characteristic X-ray diffraction spectrumwhen the crystal is prepared.

Due to such a composition, the transition of titanyl phthalocyanincrystal in organic solvents may be further reliably controlled andconsequently whether the titanyl phthalocyanin crystal is excellent instorage stability may be determined quantitatively.

It is preferable that the organic solvent is at least one selected fromthe group consisting of tetrahydrofuran, dichloromethane, toluene,1,4-dioxane and 1-methoxy-2-propanol when the titanyl Phthalocyanincrystal of present invention is prepared.

Due to such a composition, the stability of the specific titanylphthalocyanin crystal may be further reliably determined when suchorganic solvents are used as organic solvents for the coating solutionfor the photosensitive layer.

It is preferable that the structure of titanyl phthalocyanin compoundprepared form the titanyl phthalocyanin crystal of present invention isrepresented by the following general formula when the crystal isprepared.

Due to such a composition, the storage stability of titanylphthalocyanin crystal of the specific structure in organic solvents maybe further improved.

(In the general formula (1), X¹ to X⁴ are the same or differentsubstituents, each independently represents a hydrogen atom, a halogenatom, a substituted or an unsubstituted alkyl group, a substituted or anunsubstituted alkoxy group, a substituted or an unsubstituted cyanogroup or a substituted or an unsubstituted nitro group, respectively.The repeat numbers “a”, “b”, “c” and “d” represent an integer of 1 to 4,respectively and may be same or different, respectively.)

Another aspect of the present invention is a method for preparingtitanyl phthalocyanin crystal having the maximum peak at a Bragg angle2θ±0.2°=27.2° in the CuKα characteristic X-ray diffraction spectrum andone peak within the range of 270 to 400° C. other than a peakaccompanied by the vaporization of adsorbed water in the differentialscanning calorimetric analysis. Then, it is a method for preparingcharacterized by comprising the following processes (a) and (b);

(a) a process for preparing a titanyl phthalocyanin compound by adding atitanium alkoxide or titanium tetrachloride at a value within the rangeof 0.40 to 0.53 mole with respect to 1 mole of o-phthalonitrile or itsderivative or 1,3-diiminoisoindoline or its derivative and adding a ureacompound at a value within the range of 0.1 to 0.95 mole with respect to1 mole of o-phthalonitrile or its derivative or 1,3-diiminoisoindolineor its derivative to react the compounds,

(b) a process for preparing a titanyl phthalocyanin crystal byperforming an acid treatment on the titanyl phthalocyanin compoundprepared in the process (a).

That is, ammonia generated by reacting raw materials and a urea compoundfacilitates forming a complex compound with a titanium alkoxide moreefficiently by preparing the titanyl phthalocyanin crystal by the methodcomprising the above processes (a) to (b). Therefore, such a complexcompound enables to prepare the titanyl phthalocyanin crystal that ishard to change its crystal type and excellent in storage stability evenin organic solvents by further accelerating the reaction of rawmaterials.

It is preferable that the urea compound is at least one compoundselected from the group consisting of urea, thiourea, o-methylisoureasulfate, o-methylisourea carbonate and o-methylisourea hydrochloride inthe above-mentioned process (a) when the method for preparing titanylphthalocyanin crystal of the present invention is performed.

Due to such an embodiment, the titanyl phthalocyanin crystal that ishard to cause the crystal transition to the α-type crystal and β-typecrystal may be efficiently obtained by interaction of such ureacompounds and the raw materials even if the crystal is immersed in anorganic solvent for a long time, e.g., 7 days or longer. As a result,the titanyl phthalocyanin crystal with improved storage stability may beprepare at a lower cost.

It is preferable that the reaction temperature in the process (a) is setto a value of 150° C. or above when the method for preparing titanylphthalocyanin crystal of present invention is performed.

Due to such an embodiment, products generated as a vapor from thereaction system may be removed to the outside, and thereby allow toreact a titanium alkoxide or titanium tetrachloride as raw material anda urea compound.

It is preferable that the process (a) is performed in anitrogen-containing compound with a boiling point of 180° C. or abovewhen the method for preparing titanyl phthalocyanin crystal of thepresent invention is performed.

Due to such an embodiment, ammonia generated by a reaction of a ureacompound and a titanium alkoxide or titanium tetrachloride allows toform a complex with the titanium alkoxide or titanium tetrachloride. Asa result, the reaction fully proceeds, and a titanyl Phthalocyanincrystal that is hard in crystal transition in an organic solvent may beefficiently prepared in a short time.

Still more, another aspect of the present invention is anelectrophotographic photoconductor characterized by the fact that aphotosensitive layer is provided on a conductive substrate, and thephotosensitive layer contains the titanyl phthalocyanin crystal havingthe maximum peak at a Bragg angle 2θ±0.2°=27.2° in the CuKαcharacteristic X-ray diffraction spectrum and one peak within the rangeof 270 to 400° C. other than a peak accompanied by the vaporization ofadsorbed water in the differential scanning calorimetric analysis withinthe range of 0.1 to 50 part by weight with respect to 100 part by weightof a binder resin forming the photosensitive layer.

That is, an electrophotographic photoconductor having good electriccharacteristics and image characteristics may be stably obtained byusing the titanyl phthalocyanin crystal as a charge generating agenthaving little crystal transition and excellent storage stability even ifit is immersed in an organic solvent for a long time.

It is preferable that a single layer photosensitive layer containing atleast either hole transfer agent or electron transfer agent is used asthe composition of a photosensitive layer, and it is also preferablethat a single layer photosensitive layer containing both transfer agentand electron transfer agent is used as the composition of aphotosensitive layer. It is also preferable that a laminated layerconstituted by containing a charge generating layer and a chargetransfer layer containing either hole transfer agent or electrontransfer agent is used as the composition of a photosensitive layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 (a) to (c) are a schematic view for illustrating the compositionof a single layer type photoconductor.

FIGS. 2 (a) to (c) are a schematic view for illustrating the compositionof a laminated layer type photoconductor.

FIG. 3 is a spectrum for showing a CuKα characteristic X-ray diffractionof a titanyl phthalocyanin crystal (after stored for 7 days intetrahydrofuran) used in Example 1 (Examples 2 to 21 and 64 to 70).

FIG. 4 is a chart for showing a differential scanning calorimetricanalysis of a titanyl phthalocyanin crystal used in Example 1 (Examples2 to 21 and 64 to 70).

FIG. 5 is a spectrum for showing a CuKα characteristic X-ray diffractionof a titanyl phthalocyanin crystal (after stored for 7 days intetrahydrofuran) used in Example 22 (Examples 23 to 42 and 71 to 77).

FIG. 6 is a chart for showing a differential scanning calorimetricanalysis of a titanyl phthalocyanin crystal used in Example 22 (Examples23 to 42 and 71 to 77).

FIG. 7 is a spectrum for showing a CuKα characteristic X-ray diffractionof a titanyl phthalocyanin crystal (after stored for 7 days intetrahydrofuran) used in Example 43 (Examples 44 to 63 and 78 to 84).

FIG. 8 is a chart for showing a differential scanning calorimetricanalysis of a titanyl phthalocyanin crystal used in 43 (Examples 44 to63 and 78 to 84).

FIG. 9 is a spectrum for showing a CuKα characteristic X-ray diffractionof a titanyl phthalocyanin crystal (after stored for 7 days intetrahydrofuran) used in Comparative Example 1 (Comparative Examples 2to 21 and 106 to 112).

FIG. 10 is a chart for showing a differential scanning calorimetricanalysis of a titanyl phthalocyanin crystal used in Comparative Example1 (Comparative Examples 2 to 21 and 106 to 112).

FIG. 11 is a spectrum for showing a CuKα characteristic X-raydiffraction of a titanyl phthalocyanin crystal (after stored for 7 daysin tetrahydrofuran) used in Comparative Example 22 (Comparative Examples23 to 42 and 113 to 119).

FIG. 12 is a chart for showing a differential scanning calorimetricanalysis of a titanyl phthalocyanin crystal used in Comparative Example22 (Comparative Examples 23 to 42 and 113 to 119).

FIG. 13 is a spectrum for showing a CuKα characteristic X-raydiffraction of a titanyl phthalocyanin crystal (after stored for 7 daysin tetrahydrofuran) used in Comparative Example 43 (Comparative Examples44 to 63 and 120 to 126).

FIG. 14 is a chart for showing a differential scanning calorimetricanalysis of a titanyl phthalocyanin crystal used in Comparative Example43 (Comparative Examples 44 to 63 and 120 to 126).

FIG. 15 is a spectrum for showing a CuKα characteristic X-raydiffraction of a titanyl phthalocyanin crystal (after stored for 7 daysin tetrahydrofuran) used in Comparative Example 64 (Comparative Examples65 to 84 and 127 to 133).

FIG. 16 is a chart for showing a differential scanning calorimetricanalysis of a titanyl phthalocyanin crystal used in Comparative Example64 (Comparative Examples 65 to 84 and 127 to 133).

FIG. 17 is a spectrum for showing a CuKα characteristic X-raydiffraction of a titanyl phthalocyanin crystal (after stored for 7 daysin tetrahydrofuran) used in Comparative Example 85 (Comparative Examples86 to 105 and 134 to 140).

FIG. 18 is a chart for showing a differential scanning calorimetricanalysis of a titanyl phthalocyanin crystal used in Comparative Example85 (Comparative Examples 86 to 105 and 134 to 140).

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

First Embodiment of the present invention is a titanyl phthalocyanincrystal characterized by having the maximum peak at a Bragg angle2θ±0.2°=27.2° in the CuKα characteristic X-ray diffraction spectrum andone peak within the range of 270 to 400° C. other than a peakaccompanied by the vaporization of adsorbed water in the differentialscanning calorimetric analysis. The titanyl phthalocyanin crystal ofFirst Embodiment is described hereinafter by dividing it intocomponents.

1. Optical Characteristics and Thermal Characteristics

(1) Optical Characteristics

The titanyl phthalocyanin crystal as present invention is characterizedby having the maximum peak at a Bragg angle 2θ±0.2°=27.2° in the CuKαcharacteristic X-ray diffraction spectrum as an optical characteristic(first optical characteristic). It is preferable that the crystal has nopeak at a Bragg angle 2θ±0.2°=26.2° in the CuKα characteristic X-raydiffraction spectrum (second optical characteristic).

It is preferable that the crystal has no peak at a Bragg angle2θ±0.2°=7.2° in the CuKα characteristic X-ray diffraction spectrum(third optical characteristic).

This is because the stability in organic solvents when no first opticalcharacteristic tends to be significantly lower than the titanylphthalocyanin crystal having such an optical characteristic. Conversely,the storage stability in organic solvents may be improved by having thefirst optical characteristic, more preferably, the second opticalcharacteristic and the third optical characteristic.

It is preferable that the titanyl phthalocyanin crystal recovered afterbeing immersed in organic solvents for 7 days at least has the maximumpeak at a Bragg angle 2θ±0.2°=27.2° in the CuKα characteristic X-raydiffraction spectrum and no peak at a Bragg angle 2θ±0.2°=26.2°.

This is because the crystal transition of the titanyl phthalocyanincrystal in organic solvents may be more reliably controlled due to thefact that the titanyl phthalocyanin crystal may keep the above-mentionedcharacteristics even if it is immersed for 7 days in organic solvents.

It is preferable that the evaluation of immersion test in organicsolvents on the basis of evaluating the storage stability of the titanylphthalocyanin crystal is performed under the same conditions as, forexample, conditions for actually keeping a coating solution for aphotosensitive layer for preparing an electrophotographic photoconductor(called coating solution for the photosensitive layer hereinafter).Accordingly, for example, it is preferable that the storage stability ofthe titanyl phthalocyanin crystal is evaluated in a closed system underconditions of a temperature 23±1° C. and relative humidity 50 to 60% RH.

It is preferable that the organic solvent is at least one solventselected from the group consisting of tetrahydrofuran, dichloromethane,toluene, 1,4-dioxane and 1-methoxy-2-propanol in evaluating the storagestability of the titanyl phthalocyanin crystal.

This is because the stability of the specific titanyl phthalocyanincrystal may be more reliably determined and the compatibility in thespecific titanyl phthalocyanin crystal, charge transfer agent and binderresin, etc. is improved when such organic solvents are used as organicsolvents in the coating solution for the photosensitive layer.Accordingly, a photoconductor for more effectively obtainingcharacteristics of the specific titanyl phthalocyanin crystal, chargetransfer agent, etc. may be formed and an electrophotographicphotoconductor excellent in electric characteristics and imagecharacteristics may be stably constituted.

(2) Thermal Characteristics

In present invention, the titanyl phthalocyanin crystal is characterizedby having one peak within the range of 270 to 400° C. other than a peakaccompanied by the vaporization of adsorbed water in the differentialscanning calorimetric analysis.

This is because the titanyl phthalocyanin crystal having such opticalcharacteristics and thermal characteristics may effectively inhibit thecrystal transition of the crystal structure from α-type crystal toβ-type crystal even if it is added into an organic solvent and left fora long time. Accordingly, a coating solution for a photosensitive layerexcellent in storage stability may be obtained by using such a titanylphthalocyanin crystal. As a result, an electrophotographicphotoconductor excellent in electric characteristics and imagecharacteristics may be stably constituted.

The one peak that is a peak other than a peak accompanied by thevaporization of adsorbed water and appears within the range of 270 to400° C. preferably appears within the range of 290 to 400° C. and morepreferably within the range of 300 to 400° C.

A specific method for measuring the Bragg angle in the CuKαcharacteristic X-ray diffraction spectrum and a specific method of thedifferential scanning calorimetric analysis will be described in detailin examples described hereinafter.

2. Structure of Titanyl Phthalocyanin Compounds

It is preferable that titanyl phthalocyanin compounds are compoundshaving the structure represented by the above-mentioned general formula(1).

This is because not only the stability of the specific titanylphthalocyanin crystal may be further improved, but also the specifictitanyl phthalocyanin crystal may be stably prepared by using thetitanyl phthalocyanin compounds of such a structure.

It is more preferable that the structure of titanyl phthalocyanincompounds is represented by the following general formula (2). It isparticularly preferable that the titanyl phthalocyanin compounds arerepresented by the following general formula (3).

This is because such a structure of titanyl phthalocyanin allows aspecific titanyl phthalocyanin crystal having more stable property toprepare easily.

(In the general formula (2), X represents a hydrogen atom, a halogenatom, an alkyl group, an alkoxy group, a cyano group or a nitro group,and the repeat number “e” represents an integer of 1 to 4.)

Second Embodiment

Second Embodiment is a method for preparing the titanyl phthalocyanincrystal having the maximum peak at a Bragg angle 2θ±0.2°=27.2° in theCuKα characteristic X-ray diffraction spectrum and one peak within therange of 270 to 400° C. other than a peak accompanied by thevaporization of adsorbed water in the differential scanning calorimetricanalysis and is characterized by comprising the following processes (a)and (b);

(a) a process for preparing a titanyl phthalocyanin compound by adding atitanium alkoxide or titanium tetrachloride at a value within the rangeof 0.40 to 0.53 mole with respect to 1 mole of o-phthalonitrile or itsderivative or 1,3-diiminoisoindoline or its derivative and adding a ureacompound at a value within the range of 0.1 to 0.95 mole with respect to1 mole of o-phthalonitrile or its derivative or 1,3-diiminoisoindolineor its derivative to react the compounds,

(b) a process for preparing a titanyl phthalocyanin crystal byperforming an acid treatment on the titanyl phthalocyanin compoundprepared in the process (a).

The contents already described in First Embodiment are properly omittedand the above-mentioned method for preparing titanyl phthalocyanincrystal is mainly described hereinafter.

1. A Processes for Preparing a Titanyl Phthalocyanin Compound

A process for preparing a titanyl phthalocyanin compound ischaracterized by reacting o-phthalonitrile or its derivative or1,3-diiminoisoindoline or its derivative and a titanium alkoxide ortitanium tetrachloride as materials for preparing such a molecule in thepresence of a urea compound to prepare a titanyl phthalocyanin compound.

Here, the method for preparing the titanyl phthalocyanin compoundrepresented by the general formula (3) is specifically described as anexample.

That is, when the titanyl phthalocyanin compound represented by theformula (3) is prepared, it is preferably preformed according to thefollowing reaction formula (1) or the following reaction formula (2).Titanium tetrabutoxide represented by the formula (5) is used as oneexample of the titanium alkoxide in the following reaction formula (1)and the following reaction formula (2).

(1) Reaction Formula

Accordingly, it is preferable that the titanyl phthalocyanin compoundrepresented by the formula (3) is prepared by reacting o-phthalonitrilerepresented by a formula (4) and titanium tetrabutoxide as a titaniumalkoxide represented by the formula (5) as shown in the reaction formula(1) or reacting 1,3-diiminoisoindoline represented by a formula (6) anda titanium alkoxide, such as titanium tetrabutoxide, etc. represented bythe formula (5) as shown in the reaction formula (2).

Titanium tetrachloride may also be used in place of titanium alkoxidesuch as titanium tetrabutoxide, etc. represented by the formula (5).

Reaction Formula (1)

Reaction Formula (2)(2) Added Amount

The added amount of the titanium alkoxide, such as titaniumtetrabutoxide, etc., represented by the formula (5) or titaniumtetrachloride is characterized by setting to a value within the range of0.40 to 0.53 mole with respect to 1 mole of o-phthalonitrile representedby a formula (4) or its derivative or 1,3-diiminoisoindoline representedby the formula (6) or its derivative.

This is because the interaction with a urea compound describedhereinafter is effectively obtained by adding an excess of ¼ equivalentwith respect to the amount of titanium alkoxide, such as titaniumtetrabutoxide, etc., represented by the formula (5) or titaniumtetrachloride to o-phthalonitrile represented by the formula (4) or itsderivative or 1,3-diiminoisoindoline represented by the formula (6) orits derivative. Such an interaction will be described in detail in asection of urea compounds.

Accordingly, the amount of the titanium alkoxide such as titaniumtetrabutoxide, etc. represented by the formula (5) or titaniumtetrachloride is set to a value preferably within the range of 0.43 to0.50 mole and more preferably in a range of 0.45 to 0.47 mole withrespect to 1 mole of o-phthalonitrile represented by the formula (4) orits derivative or 1,3-diiminoisoindoline represented by the formula (6)or its derivative.

(3) Urea Compounds

The process (a) is characterized by performing it in the presence of aurea compound. This is because the interaction in a urea compound and atitanium alkoxide or titanium tetra-chloride is obtained by using atitanyl phthalocyanin compound prepared in the presence of a ureacompound, therefore the specific titanyl phthalocyanin crystal may beprepared.

That is, such an interaction is an action in which ammonia generated bythe reaction of a urea compound and a titanium alkoxide or titaniumtetrachloride further forms a complex with the titanium alkoxide ortitanium tetrachloride, and such a substance further accelerates thereaction represented by the reaction formulas (1) and (2). Then, atitanyl phthalocyanin crystal hard in crystal transition may beefficiently prepared even in an organic solvent by reacting the rawmaterials under such an accelerating action.

(3)-1 Types

The urea compounds used in the process (a) are preferably at least onecompound selected from the group consisting of urea, thiourea,o-methylisourea sulfate, o-methylisourea carbonate and o-methylisoureahydrochloride.

This is because ammonia generated in the process of reaction by usingsuch a urea compound as urea compound in the reaction formulas (1) and(2) allows a complex with titanium alkoxide or titanium tetrachloride toform more efficiently, and such a substance further accelerates thereaction represented by the reaction formula (1) and (2).

That is, This is because ammonia generated by reacting a titaniumalkoxide or titanium tetrachloride and a urea compound forms a complexcompound with the titanium alkoxide, etc. more efficiently andaccordingly such a complex compound further accelerates the reactionrepresented by the reaction formulas (1) and (2).

In addition, it has been known that such a complex compound allows tospecifically form when they are reacted in a high temperature conditionof 180° C. or above. Therefore, the reactions are performed moreeffectively in a nitrogen-containing compound with boiling point of 180°C. or above, e.g., quinoline (b.p.: 237.1° C.), isoquinoline (b.p.:242.5° C.) or their mixture (weight ratio 10:90 to 90:10).

Accordingly, it is more preferable to use urea in the above-mentionedurea compounds since ammonia as reaction accelerator and the complexcompound due to it allows to form easily.

(3)-2 Added Amount

The added amount of urea compounds used in the process (a) ischaracterized by setting to a value within the range of 0.1 to 0.95 molewith respect to 1 mole of o-phthalonitrile or its derivative or1,3-diiminoisoindoline or its derivative.

This is because the action of above-mentioned urea compounds may beobtained more efficiently by setting the amount of urea compounds to avalue within such a range.

Accordingly, the amount of such urea compounds is set to a value withinthe range of preferably 0.3 to 0.8 mole and more preferably 0.4 to 0.7mole with respect to 1 mole of o-phthalonitrile or its derivative or1,3-diiminoisoindoline or its derivative.

(4) Solvents

As solvents used in the process (a), for example, one or anycombinations of two or more solvent selected from the group consistingof hydrocarbon solvents such as xylene, naphthalene, methylnaphthalene,tetralin, and nitrobenzene, etc.; halogenated hydrocarbon solvents suchas dichlorobenzene, tri-chlorobenzen, dibromobenzene, andchloronaphthalene, etc.; alcohol solvents such as hexanol, octanol,decanol, benzyl alcohol, ethylene glycol, and ethylene glycol, etc.;ketone solvents such as dichlorohexanone, acetophenone,1-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone, etc.; amidesolvents such as formamide, acetamide, etc.; nitrogen-containingsolvents such as picoline, quinoline, and isoquinoline, etc. areexemplified.

Particularly, nitrogen-containing solvents of b.p. 180° C. or above,e.g., quinoline and isoquinoline are suitable in that ammonia isgenerated by reacting a titanium alkoxide or titanium tetrachloride asraw material and a urea compound allows to form a complex compound withthe titanium alkoxide, etc. more efficiently.

(5) Reaction Temperature

The reaction temperature in the process (a) is preferably a hightemperature condition of 150° C. or above. This is because the complexcompound is hard to be formed by reacting a titanium alkoxide ortitanium tetrachloride as raw material and a urea compound if such atemperature falls short of 150° C., especially lower than 135° C.Accordingly, such a complex compound becomes difficult to furtheraccelerate the reactions represented by the reaction formulas (1) and(2), thus the titanyl phthalocyanin crystal hard in crystal transitionbecomes difficult to be efficiently prepared even in an organic solvent.

Accordingly, the reaction temperature in the process (a) is preferablyset to a value within the range of 180 to 250° C., and more preferably avalue within the range of 200 to 240° C.

(6) Reaction Time

The reaction time in the process (a) is dependent upon the reactiontemperature, but it is preferably set to a range of 0.5 to 10 hrs. Thisis because a complex compound becomes hard to form by reacting atitanium alkoxide or titanium tetrachloride as raw material and a ureacompound if such a reaction time falls short of 0.5 hrs. Accordingly,such a complex compound becomes difficult to further accelerate thereactions represented by the reaction formulas (1) and (2), thus thetitanyl phthalocyanin crystal hard in crystal transition becomesdifficult to be efficiently prepared even in an organic solvent. On theother hand, if such a reaction time exceeds 10 hrs, it leads todisadvantage in economy or sometimes the formed complex compound isreduced.

Accordingly, the reaction time in the process (a) is preferably set to avalue within the range of 0.6 to 3.5 hrs, and more preferably set to avalue in a range of 0.8 to 3 hrs.

2. A processes for Preparing Titanyl Phthalocyanin Crystal

Next, it is preferable that an acid treatment as a post-treatment isperformed for the titanyl phthalocyanin compound prepared in theabove-mentioned process to obtain a titanyl Phthalocyanin crystal.

(1) Preliminary Process for Acid Treatment

As a preliminary step for performing the acid treatment, it ispreferable to perform a preliminary process for acid treatment, thetitanyl phthalocyanin compound obtained by the above-mentioned reactionsis added into a water-soluble organic solvent, stirred for apredetermined time under heating, and then the solution is allowed to beleft standing and stabilize for a predetermined time under a conditionof lower temperature than the stirring treatment.

As water-soluble organic solvents used in the process prior to acidtreatment, for example, one, two or more of alcohols such as methanol,ethanol and isopropanol, etc.; N,N-dimethylformamide,N,N-dimethylacetamide, propionic acid, acetic acid, N-methylpyrrolidone,and ethylene glycol, etc. are exemplified. A small amount of non-watersoluble organic solvents may also be added into the water-solubleorganic solvents.

Although conditions for stirring treatment in the preliminary processfor acid treatment are not specially limited, it is preferable toperform a stirring treatment of about 1 to 3 hrs under a predeterminedtemperature condition within a temperature range of about 70 to 200° C.

Although conditions for stabilization treatment after the stirringtreatment are also not specially limited, it is preferable to allow thesolution to be left standing and stabilize for about 5 to 15 hrs under apredetermined temperature condition within a temperature range of about10 to 50° C., preferably about 23±1° C.

(2) Acid Treatment Process

Next, it is preferable to perform the acid treatment process as follows.

That is, it is preferable that the titanyl phthalocyanin crystalobtained in the above-mentioned preliminary process for acid treatmentis dissolved in an acid, then the solution is dropped to water andrecrystallized, subsequently the obtained titanyl phthalocyanin crystalis washed in an aqueous alkali solution. More specifically, it ispreferable that the obtained crude crystal is dissolved in an acid, thissolution is dropped into water under ice cooling and then stirred for apredetermined time, further allowed to be left standing andrecrystallized at a temperature within the range of 10 to 30° C.Subsequently, it is preferable that the crystal is not dried and stirredat 30 to 70° C. for 2 to 8 hrs in a non-aqueous solvent in the presenceof water.

As acids used in the acid treatment, for example, concentrated sulfuricacid, trifluoroacetic acid and sulfonic acid, etc. are preferably used.

This is because impurities may be fully decomposed by using such strongacids in the acid treatment while the decomposition of the specifictitanyl phthalocyanin crystal may be inhibited. Accordingly, a titanylphthalocyanin crystal having a high-purity and excellent property incrystallinity may be obtained.

As aqueous alkali solutions used in the washing treatment, for example,common aqueous alkali solutions such as aqueous ammonia solution,aqueous sodium hydroxide solution, etc. may be preferably used.

This is because the ambience of the crystal may be made from acidity toneutrality by washing the specific titanyl phthalocyanin crystal afterthe acid treatment with such aqueous alkali solutions. As a result, thehandling of the crystal in subsequent processes may be facilitated andthe stability of the crystal may be improved.

As non-aqueous solvents for the stirring treatment, for example, halogensolvents such as chlorobenzen and dichloromethane, etc. are exemplified.

Third Embodiment

Third Embodiment is an electrophotographic photoconductor characterizedin that a photosensitive layer is provided on a conductive substrate,and the photosensitive layer comprises the titanyl phthalocyanin crystalhaving the maximum peak at a Bragg angle 2θ±0.2°=27.2° in the CuKαcharacteristic X-ray diffraction spectrum and one peak in a range of 270to 400° C. other than a peak accompanied by the vaporization of adsorbedwater in the differential scanning calorimetric analysis within therange of 0.1 to 50 part by weight with respect to 100 part by weight ofa binder resin forming the photosensitive layer.

The contents already described in Embodiments 1 and 2 are omitted andthe above-mentioned method for preparing titanyl phthalocyanin crystalis described as Third Embodiment hereinafter.

There are a single layer photoconductor and a laminated layerphotoconductor in organic photoconductors, and the present invention isapplicable to the both photoconductors.

1. Single Layer Photoconductor

(1) Basic Construction

As shown in FIG. 1(a), a single layer photoconductor 10 is provided witha single photo-sensitive layer 14 on a conductive substrate 12. Such aphotosensitive layer 14 comprises a specific titanyl phthalocyanincrystal as a charge generating agent, a charge transfer agent and abinder resin in the same layer.

The thickness of photosensitive layer is preferably set to a valuewithin the range of 5 to 100 μm, and more preferably a value within therange of 10 to 50 μm.

As shown in FIG. 1(b), the single layer photoconductor may also be aphotoconductor 10′ formed with a barrier layer 16 in a range wherecharacteristics of the photoconductor is not inhibited between theconductive substrate 12 and the photosensitive layer 14. As shown inFIG. 1(c), it may also be a photoconductor 10″ formed with a protectivelayer 18 at the surface of photosensitive layer 14.

The single layer photoconductor preferably contains either a holetransfer agent or an electron transfer agent as a charge transfer agentcontained in the photosensitive layer.

This is because characteristics of such a titanyl phthalocyanin crystalmay be fully obtained while its constitution may be performed stably andeconomically as compared with the laminated layer photoconductordescribed hereinafter. That is, an electrophotographic photoconductorhaving the good electric characteristics and image characteristics thatmay be fully obtained by the characteristics of a specific titanylphthalocyanin crystal as a charge generating agent has may beconstituted stably and economically.

The single layer photoconductor also preferably contains both a holetransfer agent and an electron transfer agent as charge transfer agents.

This is because characteristics of the specific titanyl phthalocyanincrystal may be fully obtained and a charge generated from such a titanylphthalocyanin crystal may be transferred more efficiently in an exposureprocess. As a result, an electrophotographic photoconductor havingbetter electric characteristics and image characteristics may beobtained.

(2) Charge Generating Agents

(2)-1 Types

The charge generating agent used in the photoconductor as the presentinvention is characterized by the titanyl phthalocyanin crystal havingthe maximum peak at a Bragg angle 2θ±0.2°=27.2° in the CuKαcharacteristic X-ray diffraction spectrum and one peak within the rangeof 270 to 400° C. other than a peak accompanied by the vaporization ofadsorbed water in the differential scanning calorimetric analysis.

This is because an electrophotographic photoconductor having goodelectric characteristics and image characteristics may be obtained byusing the titanyl phthalocyanin crystal that satisfies such conditions,is hard to change its crystal type and has stable characteristics evenin an organic solvent as a charge generating agent.

In addition, details on such a specific titanyl phthalocyanin crystalare already described in Embodiments 1 and 2, therefore they are omittedto avoid repetition.

Other charge generating agents may also be used together to adjust thesensitivity region of the photoconductor. As other charge generatingagents, they are not specially limited, for example, one, two or more ofpowders of inorganic photoconductive materials such as selenium,selenium-tellurium, selenium-arsenic, cadmiun sulfide and a-silicon,etc.; azo pigment, perylene pigment, anthanthrone pigment, conventionalphthalocyanin pigment other than the titanyl phthalocyanin crystal ofpresent invention, indigo pigment, triphenylmethane pigment, threnepigment, toluidine pigment, pyrazoline pigment, quinacridone pigment,and dithioketopyrrolopyrrole pigment, etc. are exemplified.

(2)-2 Added Amount

The amount of charge generating agent is characterized by setting to avalue within the range of 0.1 to 50 part by weight with respect to 100part by weight of binder resin described hereinafter.

This is because the charge generating agent may efficiently generates acharge when exposing it to the photoconductor by setting the amount ofcharge generating agent to a value within such a range.

That is, if the amount of such a charge generating agent falls short of0.1 part by weight with respect to 100 part by weight of a binder resin,the generation of charge sometimes becomes insufficient to form anelectrostatic latent image on the photoconductor. On the other hand, ifthe amount of such a charge generating agent exceeds 50 part by weightwith respect to 100 part by weight of a binder resin, uniformdistribution in a coating solution for a photosensitive layer sometimesbecomes difficult.

Accordingly, the amount of charge generating agent with respect to 100part by weight of a binder resin is preferably set to a value within therange of 0.5 to 30 part by weight.

In addition, when only the titanyl phthalocyanin crystal of presentinvention is used as a charge generating agent, the amount of chargegenerating agent is an amount of the titanyl phthalocyanin crystal; andwhen the titanyl phthalocyanin crystal of present invention is usedtogether with other charge generating agents, the amount of chargegenerating agent is the total amount of both.

When the titanyl phthalocyanin crystal as the present invention is usedtogether with other charge generating agents, the other chargegenerating agents are preferably added in a small amount in a range aslong as not disturbing the above-mentioned effects of the titanylphthalocyanin crystal. More specifically, the other charge generatingagents are preferably added in a ratio within the range of 100 part byweight or less with respect to 100 part by weight of the titanylphthalocyanin crystal.

(3) Binder Resins

As binder resins, for example, thermoplastic resins such as styrenepolymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer,styrene-maleic acid copolymer, acrylic polymer, styrene-acryliccopolymer, polyethylene, ethylene-vinyl acetate copolymer, chlorinatedpolyethylene, polyvinyl chloride, polypropylene, polyvinyl-vinylacetatecopolymer, polyester, alkyd resin, polyamide, polyurethane,polycarbonate, polyacrylate, polysulfone, diallylphthalate resin, ketoneresin, polyvinyl butyral resin, and polyether resin, etc.;cross-linkable thermosetting resins such as silicone resin, epoxy resin,phenol resin, urea resin, melamine resin, etc.; photosetting resins suchas epoxyacrylate, urethaneacrylate, etc. are exemplified. These binderresins may be used separately or used together by combining two or more.

(4) Electron Transfer Agent

(4)-1 Types

As electron transfer agents, all conventional well-known variouselectron transferable compounds are available. Particularly, electronattractive compounds such as benzoquinone compounds, diphenoquinonecompounds, naphthoquinone compounds, malononitrile, thiopyranecompounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, fluorenonecompounds [e.g., 2,4,7-trinitro-9-fluorenone, etc.], dinitrobenzene,dinitroanthracene, dinitroacridine, nitroanthraquinone, succinicanhydride, maleic anhydride, dibromomaleic anhydride,2,4,7-trinitrofluorenone imine compounds, ethylated fluorenone iminecompounds, azafluorenone compounds, dinitropyridoquinazoline compounds,thioxanthene compounds, 2-phenyl-1,4-benzoquinone compounds,2-phenyl-1,4-naphtoquinone compounds, 5,12-napthtathenquinone compounds,α-cyanostilbene compounds, 4-nitrostilbene compounds and salts of ananion radical of benzoquinone compound and a cation, etc. are suitablyused. They may be used separately or used together by combining two ormore.

Among these compounds, all electron transfer agents represented by thefollowing formulas (7) to (21) (ETM-1 to 15) have good fitting abilitysuch as compatibility for the titanyl phthalocyanin crystal as thepresent invention, etc. and are suitably used as electron transferagents excellent in electron transfer capability.

(4)-2 Added Amount

The amount of electron transfer agent is preferably set to a valuewithin the range of 20 to 500 part by weight with respect to 100 part byweight of a binder resin and more preferably a value within the range of30 to 200 part by weight with respect to 100 part by weight of thebinder resin. When an electron transfer agent and a hole transfer agentdescribed hereinafter are used together, the total amount is preferablyset to a value within the range of 20 to 500 part by weight and morepreferably a value in a range of 30 to 200 part by weight with respectto 100 part by weight of the binder resin.

When an electron transfer agent and a hole transfer agent describedlater are used together, the amount of electron transfer agent ispreferably set to a value within the range of 10 to 100 part by weightwith respect to 100 part by weight of the hole transfer agent.

(5) Hole Transfer Agent

(5)-1 Types

As hole transfer agents, all conventional well-known various electrontransferable compounds are usable. Particularly, benzidine compounds,phenylenediamine compounds, naphthylenediamine compounds,phenantolylenediamine compounds, oxadiazole compounds [e.g.,2,5-di(4-methylaminophenyl)-1,3,4-oxadiazole, etc.], styryl compounds[e.g., 9-(4-diethylamino-styryl)anthracene, etc.], carbazole compounds[e.g., poly-N-vinylcarbazole, etc.], organopolysilane compounds,pyrazoline compounds [e.g.,1-phenyl-3-(p-dimethylaminophenyl)pyrazoline, etc.], hydrazonecompounds, triphenylamine compounds, indole compounds, oxazolecompounds, isooxazole compounds, thiazole compounds, thiadizolecompounds, imidazole compounds, pyrazole compounds, triazole compounds,butadiene compounds, pyrenehydrazone compounds, acrolein compounds,carbazolehydrazone compounds, quinoline-hydrazone compounds, stilbenecompounds, stilbene-hydrazone compounds, and diphenyldiamine compounds,etc. are preferably used. They may be used separately or used togetherby combining two or more.

Among these compounds, all compounds represented by the followingformulas (22) to (46) (HTM-1 to 25) have good fitting ability such ascompatibility for the titanyl phthalocyanin crystal and are suitablyused as hole transfer agents excellent in hole transfer capability.

(5)-2 Added Amount

The amount of hole transfer agent is preferably set to a value withinthe range of 20 to 500 part by weight with respect to 100 part by weightof a binder resin and more preferably as a value in a range of 30 to 200part by weight with respect to 100 part by weight of the binder resin.When a hole transfer agent and the electron transfer agent describedabove are used together, the total amount is preferably set to a valuewithin the range of 20 to 500 part by weight and more preferably a valuewithin the range of 30 to 200 part by weight with respect to 100 part byweight of the binder resin.

(6) Other Additives

In addition to the components described above, various additives such assensitizer, fluorene compound, ultraviolet absorbent agent, plasticizer,surfactant, leveling agent, etc. may also be added in the photosensitivelayer. For example, a sensitizer such as terphenyl, halonaphthoquinones,and acenaphthylene, etc. may be used together with the charge generatingagent to improve the sensitivity of photoconductor.

(7) Conductive Substrates

As conductive substrates formed on the photosensitive layer describedabove, various materials having conductivity may be used. Conductivesubstrates formed by metals such as iron, aluminum, copper, tin,platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium,nickel, palladium, indium, stainless steel, and brass, etc., substratesmade of a plastic material which the above metal is vapor-deposited orlaminated, or glass substrates coated with aluminum iodide, tin oxide,and indium oxide, etc. are exemplified.

That is, the substrate may have conductivity in their own or theirsurface may have conductivity. The conductive substrates preferably havesufficient mechanical strength in use.

The shape of conductive substrates may be any of sheet or drum-type,etc. in conformity to the structure of used image forming device.

(8) Manufacturing Method

In constituting a single layer photoconductor, a binder resin, a chargegenerating agent, a hole transfer agent and, if necessary, an electrontransfer agent are added into a solvent, dispersed and mixed to preparea coating solution for a photosensitive layer. That is, when a singlelayer photoconductor is formed by coating process, a titanylphthalocyanin crystal as a charge generating agent, a charge transferagent and a binder resin, etc. may be dispersed and mixed with a propersolvent by a well-known method, e.g., roller mill, ball mill, attritor,paint shaker, and supersonic disperser, etc. to prepare a dispersion,then applied and dried by a well-known means.

As solvents for preparing the coating solution for the photosensitivelayer, one, two or more of tetrahydrofuran, dichloromethane, toluene,1,4-dioxane, and 1-methoxy-2-propanol, etc. are exemplified.

Furthermore, a surfactant or a leveling agent, etc. may also be added toimprove the dispersibility of the charge transfer agent or chargegenerating agent and the smoothness of surface of the photosensitivelayer in the coating solution for the photosensitive layer.

2. Laminated Photoconductor

(1) Basic Construction

As shown in FIG. 2, a laminated layer photoconductor 20 may beconstituted by forming a charge generating layer 24 containing aspecific titanyl phthalocyanin crystal as charge generating agent on asubstrate 12 by a deposition or coating means and then applying acoating solution for a photosensitive layer containing a chargegenerating agent, etc. and a binder resin on this charge generatinglayer and drying to form a charge transfer layer 22.

In contrast with the above construction, as shown in FIG. 2, the chargetransfer layer 22 may be formed on the substrate 12 and the chargegenerating layer 24 may be formed thereon.

However, the charge generating layer 24 has an extremely thin filmthickness as compared with the charge transfer layer 22, therefore, asshown in FIG. 2, the charge transfer layer 22 is more preferably formedon the charge generating layer 24 for its protection.

Either a hole transfer agent or a electron transfer agent is preferablycontained in the charge transfer layer 22.

By such a construction, a photosensitive layer may be constructed withthe above-mentioned titanyl phthalocyanin crystal, a binder resin withgood fitting ability for such a titanyl phthalocyanin crystal and asolvent, etc. with no need of especially considering the fitting abilitywith a charge transfer agent. Accordingly, characteristics of such atitanyl phthalocyanin crystal may be more effectively obtained and anelectrophotographic photoconductor excellent in electric characteristicsand image characteristics may be stably prepared.

Whether this laminated layer photoconductor becomes positively ornegatively charged type is selected according to the order of formingthe above-mentioned charge generating layer and charge transfer layerand the type of charge transfer agent used in the charge transfer layer.For example, as shown in FIG. 2, when the charge generating layer 24 isformed on the substrate 12 and the charge transfer layer 22 is formedthereon and when a hole generating agent such as amino compoundderivative or stilbene derivative is used as charge transfer agent inthe charge transfer layer 22, the photoconductor becomes the negativelycharged type. In this case, a charge transfer agent may also becontained in the charge generating layer 24. Then, if the photoconductoris such a laminated type electrophotographic photoconductor, theresidual potential of photoconductor is greatly reduced and thesensitivity may be improved.

The thickness of photosensitive layer in the laminated layerphotoconductor is preferably set to a value within the range where thethickness of charge generating layer is 0.01 to 5 μm, and morepreferably a value within the range where the thickness of chargegenerating layer is 0.1 to 3 μm.

The same substrate as the above-mentioned single layer photoconductormay be used as a substrate formed with such a photosensitive layer.

As shown in FIG. 2, an intermediate layer 25 is preferably formed onsuch a substrate 12 before the photosensitive layer is formed. This isbecause the substrate side charge is prevented from being easilyinjected into the photosensitive layer, the photosensitive layer isstrongly bound on the substrate 12 and surface defects at the substrate12 may be covered and made smooth by providing such an intermediatelayer 25.

(2) Types

When the laminated layer photoconductor of the present invention isconstituted, the types of charge generating agent, hole generating agentand binder resin and other additives may be basically the same contentsas the above-mentioned single layer photoconductor.

(3) Added Amount

The amount of charge generating agent used in the laminated layerphotoconductor of the present invention is preferably set to a valuewithin the range of 5 to 1,000 part by weight and more preferably avalue within the range of 30 to 500 part by weight with respect to 100part by weight of a binder resin constructing the charge generatinglayer.

The charge transfer agent and the binder resin constructing the chargetransfer agent may be mixed in various ratios within the range of noinhibition of charge transfer and no crystallization, but the amount ofcharge transfer agent is preferably set to a value within the range of10 to 500 part by weight and more preferably a value within the range of25 to 200 part by weight with respect to 100 part by weight of thebinder resin so that a charge generated in the charge generating layermay be easily transferred by illumination.

In addition, the amount of charge transfer agent represents a total ofthe amount of charge transfer agent and the amount of hole transferagent, when only either charge transfer agent or hole transfer agent isadded, it represents only the amount of added charge transfer agent.

(4) Manufacturing Methods

In the methods for manufacturing the charge generating layer, chargetransfer layer and intermediate layer, a binder resin is dispersed andother additives are dispersed and mixed with a proper dispersion mediumby a well-known method to prepare a coating solution for aphotosensitive layer, respectively, then the coating solution is appliedby a well-known method and dried, respectively.

EXAMPLES

Hereinafter, the present invention will be concretely described withreference to examples thereof.

Example 1

1. Preparation of Titanyl Phthalocyanin

To an argon-substituted flask, 22 g (0.17 mole) of o-phthalonitrile, 25g (0.073 mole) of titanium tetrabutoxide, 2.28 g (0.038 mole) of ureaand 300 g of quinone were added and heated up to 150° C. while stirring.Next, the mixture was heated up to 215° C. while removing a vaporgenerated from the reaction system to the outside, then stirred andreacted for additional 2 hrs while keeping this reaction temperature.

After the reaction finished, the reaction mixture was withdrawn from theflask at a time of cooling it to 150° C., filtered with a glass filter,the resultant solid was washed with N,N-dimethylformamide and methanolin order, vacuum dried and 24 g of a blue-purple solid was obtained

2. Preparation for Titanyl Phthalocyanin Crystal

(1) Preliminary Process for Acid Treatment

10 g of the blue-purple solid obtained in the above-mentionedpreparation of the titanyl phthalocyanin was added in 100 mL ofN,N-dimethylformamide, heated up to 130° C. while stirring and thenstirred for 2 hrs. Next, the heating was stopped after a lapse of 2 hrs,the mixture was cooled to 23±1° C., then the stirring was stopped, theliquid was allowed to be left standing for 12 hrs in this state toperform a stabilization treatment. Subsequently, the stabilized liquidwas filtered with a glass filter, the obtained solid was washed withmethanol, vacuum dried and 9.83 g of a crude crystal of titanylphthalocyanin compound was obtained.

(2) A Process for Acid Treatment

5 g of the crude crystal of titanyl phthalocyanin compound obtained inthe above-mentioned preliminary process of acid treatment was added to100 ml of concentrated sulfuric acid and dissolved. Next, the solutionwas dropped into water under ice cooling and then stirred at roomtemperature for 15 min, further allowed to be left standing near 23±1°C. for 30 min and recrystallized. Next, the above-mentioned liquid wasfiltered with a glass filter, the obtained solid was washed with wateruntil the wash solution became neutral, then dispersed in 200 ml ofchlorobenzen, heated to 50° C. and stirred for 10 hrs in a state thatwater existed without being dried. Subsequently, the liquid was filteredwith a glass filter, and then the obtained solid was vacuum dried at 50°C. for 5 hrs and 4.1 g of a non-substituted titanyl phthalocyanincrystal (a blue powder) represented by the formula (3) was obtained.

3. Optical Characteristics and Thermal Characteristics

(1) Measurement of CuKα Characteristic X-Ray Diffraction Spectrum

0.3 g of the obtained titanyl phthalocyanin within 60 min afterpreparation was dispersed in 5 g of tetrahydrofuran, kept in a closedsystem for 7 days under conditions of temperature 23±1° C. and relativehumidity 50 to 60% RH, and then packed in a sample holder of an X-raydiffractometer (RINT1100 made by Rigaku Denki, Inc.) and measured.

Measuring conditions were as follows for both initial measurement andre-measurement.

X-ray tube ball: Cu

Tube voltage: 40 kV

Tube current: 30 mA

Start angle: 3.0°

Stop angle: 40.0°

Scanning speed: 10°/min

The CuKα characteristic X-ray diffraction spectrum was evaluated by thefollowing criteria. The obtained results are shown in Table 1 and FIG.3.

∘: A strong peak exists at a Bragg angle 2θ±0.2°=27.2° and no peaks at7.2° and 26.2°.

x: A small peak at a Bragg angle 2θ±0.2°=27.2° and a strong peak at26.2°.

(2) Differential Scanning Calorimetric Analysis

The differential scanning calorimetric analysis of the obtained titanylphthalocyanin crystal was performed by a differential scanningcalorimeter (TAS-200 model, DSC8230D made by Rigaku Denki, Inc.).Measurement conditions are as follows. A differential scanningcalorimetric analysis chart is shown in FIG. 4, but one peak wasobserved at 296° C.

Sample pan: aluminum

Heating rate: 20° C./min

4. Constitution of Single Layer Photoconductor

5 part by weight of the obtained titanyl phthalocyanin crystal, 70 partby weight of a hole transfer agent represented by the formula (22)(HTM-1), 30 part by weight of an electron transfer agent represented bythe formula (7) (ETM-1) and 100 part by weight of a polycarbonate(TS2020 made by Teijin Chemical, Ltd.) as a binder resin as well as 800part by weight of tetrahydrofuran were mixed and dispersed together by asupersonic disperser and a coating solution for single layerphotosensitive layer was the prepared.

Next, this coating solution for the photosensitive layer was applied toan aluminum drum-type support of 30 mm in diameter and 254 mm in totallength by dip coating process within about 60 min immediately afterpreparing. Subsequently, an electrophotographic photoconductor having asingle layer photosensitive layer of 25 μm in film thickness wasconstituted by heat treatment at 130° C. for 30 min.

The above-mentioned coating solution for the photosensitive layer wasstored for 7 days in a closed system at temperature 23±1° C. andrelative humidity 50 to 60% RH. Next, it was dispersed again by asupersonic disperser and then applied to an aluminum drum-type supportof 30 mm in diameter and 254 mm in total length as conductive substrateby using dip coating process in the same manner. Subsequently, a singlelayer photoconductor of 25 μm in film thickness was constituted by heattreatment at 130° C. for 30 min.

5. Evaluation of Single Layer Photoconductor

(1) Electric Characteristics

The bright potential Vr1 (V) of the photosensitive layer formed with acoating solution for a photosensitive layer for the single layerphotosensitive layer immediately after preparation and the darkpotential Vr2 (V) of the photosensitive layer formed with a coatingsolution for a photosensitive layer after 7 day storage were measuredunder the following conditions, respectively.

That is, the prepared electrophotographic photoconductor was charged ona surface potential +700 V by corona discharge using a drum sensitivitytester under a normal temperature condition and a normal humiditycondition (temperature: 20° C. and humidity: 60%).

Next, a light of light intensity 8 μm/cm², which was monochromatized toa wavelength 780 nm and a half-value width 20 nm, was exposed for 1.5sec at the surface of the electrophotographic photoconductor with aband-pass filter while the surface potential after 0.5 sec from thestart of exposure was measured as bright potential. Then, ΔVr (V)(=Vr2−Vr1) was calculated and evaluated by the following criteria as anelectric characteristic of the photosensitive layer from the absolutevalue of bright potential change. The obtained result is shown in Table1.

+ (excellent): The absolute value of bright potential change falls shortof 10 V.

− (poor): The absolute value of bright potential change is 10 V orabove.

(2) Image Fogging

Image formation was performed under a high temperature condition and ahigh humidity condition (temperature: 35° C. and humidity: 85%) by aprinter FS1010 (made by Kyocera, Ltd.) loaded with anelectrophotographic photoconductor which was constituted with thecoating solution for the photosensitive layer after 7 day storage toprint ISO 5% continuous 200,000 pieces and ISO 2% intermittent 50,000pieces.

Next, the density of non-printing area in printing ISO 5% continuous200,000 pieces and ISO 2% intermittent 50,000 pieces was measured by aspectrophotometer SpectroEye (manufactured by GretagMacbeth, Ltd.), andthe image fogging was estimated by the following criteria. The obtainedresult is shown in Table 1.

++ (excellent): The density of non-printing area falls short of 0.008and no any poor fogging was observed.

+ (acceptable): The density of non-printing area is more than 0.008 andfalls short of 0.015 and a little poor fogging was observed.

− (poor): The density of non-printing area is more than 0.015 andremarkable poor fogging was observed.

Examples 2 to 21

Effects of the types of hole transfer agents and electron transferagents were investigated in Examples 2 to 21. That is, the preparationof titanyl phthalocyanin crystals and the constitution of single layerphotoconductors were performed and evaluated in the same manner asExample 1, respectively except that hole transfer agents (HTM-1 to 7)and electron transfer agents (ETM-1 to 3) as shown in Table 1 were usedin place of the hole transfer agent (HTM-1) and the electron transferagent (ETM-1) used in Example 1 in constituting photoconductors,respectively. The obtained results are shown in Table 1.

A titanyl phthalocyanin crystal used in Examples 2 to 21 is same as inExample 1, therefore the CuKα characteristic X-ray diffraction spectrumand the differential scanning calorimetric analysis chart are same as inExample 1.

Examples 22 to 42

An effect of the amount of urea used in preparing titanyl phthalocyanincompounds was investigated in Examples 22 to 42.

That is, the preparation of titanyl phthalocyanin crystals and theconstitution of single layer photoconductors were performed andevaluated in the same manner as Examples 1 to 21, respectively exceptthat the amount of urea used in preparing titanyl phthalocyanincompounds was 5.70 g (0.095 mole) in place of 2.28 g (0.038 mole) usedin Examples 1 to 21, respectively. The obtained results are shown inTable 1, FIG. 5 and FIG. 6.

Examples 43 to 63

An effect of the amount of urea used in preparing titanyl phthalocyanincompounds was investigated in Examples 43 to 63.

That is, the preparation of titanyl phthalocyanin crystals and theconstitution of single layer photoconductors were performed andevaluated in the same manner as Examples 1 to 21, respectively exceptthat the amount of urea used in preparing titanyl phthalocyanincompounds was 8.40 g (0.14 mole) in place of 2.28 g (0.038 mole) used inExamples 1 to 21, respectively. The obtained results are shown in Table1, FIG. 7 and FIG. 8.

Comparative Examples 1 to 21

The preparation of titanyl phthalocyanin crystals and the constitutionof single layer photoconductors were performed and evaluated in the samemanner as Examples 1 to 21, respectively except that urea was not usedin preparing titanyl phthalocyanin compounds in Comparative examples 1to 21, respectively. The obtained results are shown in Table 2, FIG. 9and FIG. 10.

Comparative Examples 22 to 42

The preparation of titanyl phthalocyanin crystals and the constitutionof single layer photoconductors were performed and evaluated in the samemanner as Examples 1 to 21, respectively except that 2 g of anon-crystalline titanyl phthalocyanin compound in the preliminary stepof acid treatment in Comparative examples 1 to 21 was put into a glassbeaker and dimethylene glycol dimethylether was added until the totalamount became 200 mL in preparing the titanyl phthalocyanin crystal,respectively, subsequently it was stirred at 23±1° C. for 24 hrs to givea titanyl Phthalocyanin crystal in Comparative examples 22 to 42. Theobtained results are shown in Table 2, FIG. 11 and FIG. 12.

Comparative Examples 43 to 63

In Comparative examples 43 to 63, 5 g of a crude non-crystalline titanylphthalocyanin crystal after the preliminary process of acid treatment inComparative examples 1 to 21 was added to 100 ml of a mixed solvent ofdichloromethane and trifluoroacetic acid (volume ratio 4:1) anddissolved. Next, this solution was dropped into a mixed lean solvent ofmethanol and water (volume ratio 1:1), then stirred at room temperaturefor 15 min, allowed to be left standing and recrystallized at 23±1° C.for 30 min. Next, the above-mentioned liquid was filtered with a glassfilter, the obtained solid was washed with water until the wash solutionbecame neutral, then dispersed in 200 ml of chlorobenzen and stirred atroom temperature for 1 hr in a state that water existed without beingdried at 50° C. for 5 hrs. Subsequently, the solution was filtered witha glass filter, then the obtained solid was vacuum dried and 4.2 g of anon-substituted titanyl phthalocyanin crystal (blue powder) representedby the formula (3) was obtained.

Besides, the preparation of titanyl phthalocyanin crystal and theconstitution of single layer photoconductor were performed and evaluatedin the same manner as Comparative examples 1 to 21, respectively. Theobtained results are shown in Table 2, FIG. 13 and FIG. 14.

Comparative Examples 64 to 84

The preparation of titanyl phthalocyanin crystal and the constitution ofsingle layer photoconductor were performed and evaluated in the samemanner as Examples 22 to 42, respectively except that the amount oftitanium tetrabutoxide used in preparing a titanyl phthalocyanin crystalwas 15.0 g (0.044 mole) in Comparative examples 64 to 84 in place of25.0 g (0.073 mole) in Examples 22 to 42. The obtained results are shownin Table 3, FIG. 15 and FIG. 16.

Comparative Examples 85 to 105

The preparation of titanyl phthalocyanin crystal and the constitution ofsingle layer photoconductor were performed and evaluated in the samemanner as Examples 1 to 21, respectively except that the amount of ureaused in preparing a titanyl phthalocyanin crystal was 20.25 g (0.342mole) in Comparative examples 85 to 105 in place of 2.28 g (0.038 mole)in Examples 1 to 21. The obtained results are shown in Table 3, FIG. 17and FIG. 18. TABLE 1 Bragg Angle DSC Peak Electric Characteristic 2θ ±0.2° Temp. Number Bright Potential Peak Evaluation (° C.) (peak) HTM ETMChange (V) Evaluation Image Fog Example 1 ◯ 296 1 HTM-1 ETM-1 1 ◯ ◯Example 2 ETM-2 0 ◯ ◯ Example 3 ETM-3 −2 ◯ ◯ Example 4 HTM-2 ETM-1 1 ◯ ◯Example 5 ETM-2 1 ◯ ◯ Example 6 ETM-3 1 ◯ ◯ Example 7 HTM-3 ETM-1 2 ◯ ◯Example 8 ETM-2 −3 ◯ ◯ Example 9 ETM-3 2 ◯ ◯ Example 10 HTM-4 ETM-1 2 ◯◯ Example 11 ETM-2 −2 ◯ ◯ Example 12 ETM-3 2 ◯ ◯ Example 13 HTM-5 ETM-1−1 ◯ ◯ Example 14 ETM-2 −1 ◯ ◯ Example 15 ETM-3 0 ◯ ◯ Example 16 HTM-6ETM-1 7 ◯ ◯ Example 17 ETM-2 5 ◯ ◯ Example 18 ETM-3 3 ◯ ◯ Example 19HTM-7 ETM-1 2 ◯ ◯ Example 20 ETM-2 −1 ◯ ◯ Example 21 ETM-3 3 ◯ ◯ Example22 ◯ 327 1 HTM-1 ETM-1 1 ◯ ◯ Example 23 ETM-2 0 ◯ ◯ Example 24 ETM-3 6 ◯◯ Example 25 HTM-2 ETM-1 5 ◯ ◯ Example 26 ETM-2 4 ◯ ◯ Example 27 ETM-3 6◯ ◯ Example 28 HTM-3 ETM-1 −1 ◯ ◯ Example 29 ETM-2 −3 ◯ ◯ Example 30ETM-3 2 ◯ ◯ Example 31 HTM-4 ETM-1 3 ◯ ◯ Example 32 ETM-2 3 ◯ ◯ Example33 ETM-3 −1 ◯ ◯ Example 34 HTM-5 ETM-1 2 ◯ ◯ Example 35 ETM-2 −3 ◯ ◯Example 36 ETM-3 4 ◯ ◯ Example 37 HTM-6 ETM-1 2 ◯ ◯ Example 38 ETM-2 4 ◯◯ Example 39 ETM-3 −2 ◯ ◯ Example 40 HTM-7 ETM-1 2 ◯ ◯ Example 41 ETM-20 ◯ ◯ Example 42 ETM-3 4 ◯ ◯ Example 43 ◯ 372 1 HTM-1 ETM-1 1 ◯ ◯Example 44 ETM-2 3 ◯ ◯ Example 45 ETM-3 2 ◯ ◯ Example 46 HTM-2 ETM-1 1 ◯◯ Example 47 ETM-2 1 ◯ ◯ Example 48 ETM-3 2 ◯ ◯ Example 49 HTM-3 ETM-1−1 ◯ ◯ Example 50 ETM-2 −3 ◯ ◯ Example 51 ETM-3 2 ◯ ◯ Example 52 HTM-4ETM-1 1 ◯ ◯ Example 53 ETM-2 −1 ◯ ◯ Example 54 ETM-3 3 ◯ ◯ Example 55HTM-5 ETM-1 3 ◯ ◯ Example 56 ETM-2 3 ◯ ◯ Example 57 ETM-3 2 ◯ ◯ Example58 HTM-6 ETM-1 2 ◯ ◯ Example 59 ETM-2 0 ◯ ◯ Example 60 ETM-3 −3 ◯ ◯Example 61 HTM-7 ETM-1 2 ◯ ◯ Example 62 ETM-2 1 ◯ ◯ Example 63 ETM-3 1 ◯◯

TABLE 2 Bragg Angle DSC Peak Electric Characteristic 2θ ± 0.2° Temp.Number Bright Potential Peak Evaluation (° C.) (peak) HTM ETM Change (V)Evaluation Image Fog Comparative example 1 ◯ none 0 HTM-1 ETM-1 1 ◯ ΔComparative example 2 ETM-2 3 ◯ Δ Comparative example 3 ETM-3 2 ◯ ΔComparative example 4 HTM-2 ETM-1 1 ◯ Δ Comparative example 5 ETM-2 1 ◯Δ Comparative example 6 ETM-3 2 ◯ Δ Comparative example 7 HTM-3 ETM-1 −1◯ Δ Comparative example 8 ETM-2 −3 ◯ Δ Comparative example 9 ETM-3 2 ◯ ΔComparative example 10 HTM-4 ETM-1 1 ◯ Δ Comparative example 11 ETM-2 −1◯ Δ Comparative example 12 ETM-3 3 ◯ Δ Comparative example 13 HTM-5ETM-1 3 ◯ Δ Comparative example 14 ETM-2 3 ◯ Δ Comparative example 15ETM-3 2 ◯ Δ Comparative example 16 HTM-6 ETM-1 2 ◯ Δ Comparative example17 ETM-2 0 ◯ Δ Comparative example 18 ETM-3 −3 ◯ Δ Comparative example19 HTM-7 ETM-1 2 ◯ Δ Comparative example 20 ETM-2 1 ◯ Δ Comparativeexample 21 ETM-3 1 ◯ Δ Comparative example 22 X 232 1 HTM-1 ETM-1 425 XX Comparative example 23 ETM-2 426 X X Comparative example 24 ETM-3 433X X Comparative example 25 HTM-2 ETM-1 424 X X Comparative example 26ETM-2 427 X X Comparative example 27 ETM-3 431 X X Comparative example28 HTM-3 ETM-1 419 X X Comparative example 29 ETM-2 431 X X Comparativeexample 30 ETM-3 421 X X Comparative example 31 HTM-4 ETM-1 441 X XComparative example 32 ETM-2 422 X X Comparative example 33 ETM-3 433 XX Comparative example 34 HTM-5 ETM-1 424 X X Comparative example 35ETM-2 422 X X Comparative example 36 ETM-3 434 X X Comparative example37 HTM-6 ETM-1 412 X X Comparative example 38 ETM-2 434 X X Comparativeexample 39 ETM-3 422 X X Comparative example 40 HTM-7 ETM-1 427 X XComparative example 41 ETM-2 424 X X Comparative example 42 ETM-3 427 XX Comparative example 43 ◯ none 0 HTM-1 ETM-1 16 X X Comparative example44 ETM-2 11 X X Comparative example 45 ETM-3 18 X X Comparative example46 HTM-2 ETM-1 21 X X Comparative example 47 ETM-2 19 X X Comparativeexample 48 ETM-3 16 X X Comparative example 49 HTM-3 ETM-1 15 X XComparative example 50 ETM-2 15 X X Comparative example 51 ETM-3 13 X XComparative example 52 HTM-4 ETM-1 17 X X Comparative example 53 ETM-217 X X Comparative example 54 ETM-3 16 X X Comparative example 55 HTM-5ETM-1 11 X X Comparative example 56 ETM-2 16 X X Comparative example 57ETM-3 19 X X Comparative example 58 HTM-6 ETM-1 20 X X Comparativeexample 59 ETM-2 28 X X Comparative example 60 ETM-3 22 X X Comparativeexample 61 HTM-7 ETM-1 16 X X Comparative example 62 ETM-2 18 X XComparative example 63 ETM-3 14 X X

TABLE 3 Bragg Angle DSC Peak Electric Characteristic 2θ ± 0.2° Temp.Number Bright Potential Peak Evaluation (° C.) (peak) HTM ETM Change (V)Evaluation Image Fog Comparative example 64 ◯ none 0 HTM-1 ETM-1 18 X XComparative example 65 ETM-2 16 X X Comparative example 66 ETM-3 14 X XComparative example 67 HTM-2 ETM-1 12 X X Comparative example 68 ETM-212 X X Comparative example 69 ETM-3 13 X X Comparative example 70 HTM-3ETM-1 16 X X Comparative example 71 ETM-2 15 X X Comparative example 72ETM-3 17 X X Comparative example 73 HTM-4 ETM-1 24 X X Comparativeexample 74 ETM-2 26 X X Comparative example 75 ETM-3 25 X X Comparativeexample 76 HTM-5 ETM-1 24 X X Comparative example 77 ETM-2 26 X XComparative example 78 ETM-3 28 X X Comparative example 79 HTM-6 ETM-121 X X Comparative example 80 ETM-2 24 X X Comparative example 81 ETM-322 X X Comparative example 82 HTM-7 ETM-1 16 X X Comparative example 83ETM-2 16 X X Comparative example 84 ETM-3 14 X X Comparative example 85◯ none 0 HTM-1 ETM-1 2 ◯ X Comparative example 86 ETM-2 3 ◯ XComparative example 87 ETM-3 1 ◯ X Comparative example 88 HTM-2 ETM-1 −2◯ X Comparative example 89 ETM-2 −2 ◯ X Comparative example 90 ETM-3 2 ◯X Comparative example 91 HTM-3 ETM-1 −1 ◯ X Comparative example 92 ETM-23 ◯ X Comparative example 93 ETM-3 4 ◯ X Comparative example 94 HTM-4ETM-1 4 ◯ X Comparative example 95 ETM-2 2 ◯ X Comparative example 96ETM-3 2 ◯ X Comparative example 97 HTM-5 ETM-1 6 ◯ X Comparative example98 ETM-2 3 ◯ X Comparative example 99 ETM-3 3 ◯ X Comparative example100 HTM-6 ETM-1 5 ◯ X Comparative example 101 ETM-2 −2 ◯ X Comparativeexample 102 ETM-3 2 ◯ X Comparative example 103 HTM-7 ETM-1 −2 ◯ XComparative example 104 ETM-2 3 ◯ X Comparative example 105 ETM-3 3 ◯ X

Example 64

A laminated layer photoconductor was constituted as shown below bypreparing a titanyl phthalocyanin crystal in the same manner as Examples1 to 21 and using it as a charge generating agent and using the holetransfer agent (HTM-1) represented by the formula (22) as a holetransfer agent in Example 64. It was evaluated in the same manner asExamples 1 to 21 except that Microline 22N manufactured by Oki Electric,Ltd. as an evaluating machine in the evaluation of image fogging. Theresult is shown in Table 4.

In addition, the titanyl phthalocyanin crystal used is same as inExamples 1 to 21, therefore the presentation of the CuKα characteristicX-ray diffraction spectrum and the differential scanning calorimetricanalysis chart is omitted. The manufacturing method of the laminatedlayer photoconductor of Example 64 is shown hereinafter.

1. Constitution of Laminated Layer Photoconductor

(1) Intermediate Layer

2.5 part by weight of titanium oxide (MT-02 (number-average primaryparticle diameter 10 nm) manufactured by Teika, Ltd.) that wassurface-treated with alumina and silica and then with methyl-hydrogenpolysiloxane, 1 part by weight of Amilan CM8000 (made by Toray Inc.)that was a 6, 12, 66, 610 four-dimensional polymerized polyamide resin,10 part by weight of methanol and 2.5 part by weight of butanol werereceived in a paint shaker and then dispersed for 10 hrs to prepare acoating solution for a photosensitive layer for intermediate layer.

The obtained coating solution for the photosensitive layer was filteredwith a 5 μm filter and then applied to an aluminum drum-type supportsubstrate of 30 mm in diameter and 238.5 mm in total length as aconductive substrate. Subsequently, it was heat-treated at 130° C. for30 min to form an intermediate layer of 2 μm in film thickness.

(2) Charge Generating Layer

Next, 1 part by weight of the titanyl phthalocyanin crystal prepared asa charge generating agent by Example 1, 1 part by weight of a polyvinylacetal resin (Eslek KS-5 made by Sekisui Chemical, Ltd.) being a binderresin, 60 part by weight of propylene glycol monomethyl ether being adispersion medium and 20 part by weight of tetrahydrofuran were mixedfor 48 hrs and then dispersed by a ball mill to form a coating solutionfor a photosensitive layer for charge generating layer.

The obtained coating solution for the photosensitive layer was filteredwith a 3 μm filter, then applied onto the above-mentioned intermediatelayer and dried at 80° C. for 5 min to form a charge generating layer of0.3 μm in film thickness.

(3) Charge Transfer Layer

Next, 70 part by weight of the hole transfer agent (HTM-1) representedby the formula (22), 100 part by weight of a polycarbonate being abinder resin were mixed and dissolved with 460 part by weight oftetrahydrofuran to prepare a coating solution for a photosensitive layerfor charge transfer layer.

Next, this coating solution for the photosensitive layer was appliedonto the charge generating layer as the coating solution for thephotosensitive layer for charge generating layer within 60 min after itwas prepared, in the same manner. Subsequently, it was dried at 130° C.for 30 min to form a charge transfer layer of 20 μm in film thickness.These layers were make into an electrophotographic photoconductor havinga laminated photosensitive layer as a whole.

The above-mentioned coating solutions for the photosensitive layer werestored for 7 days in a closed system of temperature 23±1° C. andrelative humidity 50 to 60% RH, next dispersed again by using asupersonic disperser and then applied, in the same manner, by theabove-mentioned method for constituting an electrophotographicphotoconductor having a laminated photosensitive layer.

Examples 65 to 70

Laminated layer photoconductors were constituted and evaluated in thesame manner as Example 64, respectively except that the hole transferagents (HTM-2 to 7) shown in Table 2 were used in Examples 65 to 70 inplace of the hole transfer agent (HTM-1) used in Example 64 inconstituting the photoconductors, respectively. The results are shown inTable 4.

A titanyl phthalocyanin crystal used is same as in Examples 1 to 21,therefore the description of the CuKα characteristic X-ray diffractionspectrum and the differential scanning calorimetric analysis chart isomitted

Examples 71 to 77

Laminated layer photoconductors were constituted and evaluated in thesame manner as Examples 64 to 70, respectively in Examples 71 to 77except that the titanyl phthalocyanin crystal was prepared in the samemanner as Examples 22 to 42. The results are shown in Table 4.

The titanyl phthalocyanin crystal used is same as in Examples 22 to 42,therefore the presentation of the CuKα characteristic X-ray diffractionspectrum and the differential scanning calorimetric analysis chart isomitted.

Examples 78 to 84

Laminated layer photoconductors were constituted and evaluated in thesame manner as Examples 64 to 70, respectively in Examples 78 to 84except that the titanyl phthalocyanin crystal was prepared in the samemanner as Examples 43 to 63. The results are shown in Table 4.

The titanyl phthalocyanin crystal used is same as in Examples 43 to 63,therefore the presentation of the CuKα characteristic X-ray diffractionspectrum and the differential scanning calorimetric analysis chart isomitted.

Comparative Examples 106 to 112

Laminated layer photoconductors were constituted and evaluated in thesame manner as Examples 64 to 70, respectively in Comparative examples106 to 112 except that the titanyl phthalocyanin crystal was prepared inthe same manner as Comparative examples 1 to 21. The results are shownin Table 4.

The titanyl phthalocyanin crystal used is same as in Comparativeexamples 1 to 21, therefore the description of the CuKα characteristicX-ray diffraction spectrum and the differential scanning calorimetricanalysis chart is omitted.

Comparative Examples 113 to 119

Laminated layer photoconductors were constituted and evaluated in thesame manner as Examples 64 to 70, respectively in Comparative examples113 to 119 except that the titanyl phthalocyanin crystal was prepared inthe same manner as Comparative examples 22 to 42. The results are shownin Table 4.

The titanyl phthalocyanin crystal used is same as in Comparativeexamples 22 to 42, therefore the description of the CuKα characteristicX-ray diffraction spectrum and the differential scanning calorimetricanalysis chart is omitted.

Comparative Examples 120 to 126

Laminated layer photoconductors were constituted and evaluated in thesame manner as Examples 64 to 70, respectively in Comparative examples120 to 126 except that the titanyl phthalocyanin crystal was prepared inthe same manner as Comparative examples 4.3 to 63. The results are shownin Table 4.

The titanyl phthalocyanin crystal used is same as in Comparativeexamples 43 to 63, therefore the description of the CuKα characteristicX-ray diffraction spectrum and the differential scanning calorimetricanalysis chart is omitted.

Comparative Examples 127 to 133

Laminated layer photoconductors were constituted and evaluated in thesame manner as Examples 64 to 70, respectively in Comparative examples127 to 133 except that the titanyl phthalocyanin crystal was prepared inthe same manner as Comparative examples 64 to 84. The results are shownin Table 4.

The tithanylphthalocyanine crystal used is same as in Comparativeexamples 64 to 84, therefore the description of the CuKα characteristicX-ray diffraction spectrum and the differential scanning calorimetricanalysis chart is omitted.

Comparative Examples 134 to 140

Laminated layer photoconductors were constituted and evaluated in thesame manner as Examples 64 to 70, respectively in Comparative examples134 to 140 except that the titanyl phthalocyanin crystal was prepared inthe same manner as Comparative examples 85 to 105. The results are shownin Table 4. The titanyl phthalocyanin crystal used is same as inComparative examples 85 to 105, therefore the description of the CuKαcharacteristic X-ray diffraction spectrum and the differential scanningcalorimetric analysis chart is omitted. TABLE 4 Bragg Angle DSC PeakElectric Characteristic 2θ ± 0.2° Temp. Number Bright Potential PeakEvaluation (° C.) (peak) HTM Change (V) Evaluation Image Fog Example 64◯ 296 1 HTM-1 2 ◯ ◯ Example 65 HTM-2 1 ◯ ◯ Example 66 HTM-3 0 ◯ ◯Example 67 HTM-4 3 ◯ ◯ Example 68 HTM-5 4 ◯ ◯ Example 69 HTM-6 5 ◯ ◯Example 70 HTM-7 2 ◯ ◯ Example 71 ◯ 327 1 HTM-1 2 ◯ ◯ Example 72 HTM-2 4◯ ◯ Example 73 HTM-3 3 ◯ ◯ Example 74 HTM-4 1 ◯ ◯ Example 75 HTM-5 0 ◯ ◯Example 76 HTM-6 2 ◯ ◯ Example 77 HTM-7 −2 ◯ ◯ Example 78 ◯ 372 1 HTM-12 ◯ ◯ Example 79 HTM-2 4 ◯ ◯ Example 80 HTM-3 3 ◯ ◯ Example 81 HTM-4 1 ◯◯ Example 82 HTM-5 0 ◯ ◯ Example 83 HTM-6 2 ◯ ◯ Example 84 HTM-7 −2 ◯ ◯Comparative example 106 ◯ none 0 HTM-1 1 ◯ Δ Comparative example 107HTM-2 −3 ◯ Δ Comparative example 108 HTM-3 2 ◯ Δ Comparative example 109HTM-4 2 ◯ Δ Comparative example 110 HTM-5 0 ◯ Δ Comparative example 111HTM-6 3 ◯ Δ Comparative example 112 HTM-7 −2 ◯ Δ Comparative example 113X 232 1 HTM-1 62 X X Comparative example 114 HTM-2 61 X X Comparativeexample 115 HTM-3 62 X X Comparative example 116 HTM-4 61 X XComparative example 117 HTM-5 71 X X Comparative example 118 HTM-6 64 XX Comparative example 119 HTM-7 76 X X Comparative example 120 ◯ none 0HTM-1 16 X X Comparative example 121 HTM-2 19 X X Comparative example122 HTM-3 11 X X Comparative example 123 HTM-4 15 X X Comparativeexample 124 HTM-5 18 X X Comparative example 125 HTM-6 15 X XComparative example 126 HTM-7 31 X X Comparative example 127 ◯ none 0HTM-1 12 X X Comparative example 128 HTM-2 16 X X Comparative example129 HTM-3 17 X X Comparative example 130 HTM-4 11 X X Comparativeexample 131 HTM-5 12 X X Comparative example 132 HTM-6 12 X XComparative example 133 HTM-7 16 X X Comparative example 134 ◯ none 0HTM-1 2 ◯ X Comparative example 135 HTM-2 4 ◯ X Comparative example 136HTM-3 −2 ◯ X Comparative example 137 HTM-4 3 ◯ X Comparative example 138HTM-5 5 ◯ X Comparative example 139 HTM-6 −1 ◯ X Comparative example 140HTM-7 0 ◯ X

Here, the mole number of titanium tetrabutoxide and urea added withrespect to 1 mole of o-phthalonitrile and the mole number of urea in allthe examples and comparative examples are shown in Table 5. TABLE 5Titanium Tetrabutoxide (mole)/ Urea (mole)/ o-Phthalonitrileo-Phthalonitrile (mole) (mole) Examples 1 to 21 and 0.43 0.22 Examples64 to 70 Examples 22 to 42 and 0.43 0.56 Examples 71 to 77 Examples 43to 63 and 0.43 0.82 Examples 78 to 84 Comparative Examples 0.43 0 1 to21 and Comparative Examples 106 to 112 Comparative Examples 0.43 0 22 to42 and Comparative Examples 113 to 119 Comparative Examples 0.43 0 43 to63 and Comparative Examples 120 to 126 Comparative Examples 0.26 0.56 64to 84 and Comparative Examples 127 to 133 Comparative Examples 0.43 2.085 to 105 and Comparative Examples 134 to 140

INDUSTRIAL APPLICABILITY

According to the titanyl phthalocyanin crystal in the present invention,the storage stability in organic solvents could be sufficiently improvedas compared with the conventional titanyl phthalocyanin crystal byhaving a peak at a predetermined Bragg angle in the CuKα characteristicX-ray diffraction spectrum and one peak within a predeterminedtemperature range in the differential scanning calorimetric analysis.

According to the method for preparing the titanyl phthalocyanin crystalin the present invention, the titanyl phthalocyanin crystal which ishard to transit the crystal to not only α-type but also β-type even inorganic solvents was obtained with significant efficiency and at a lowcost by reacting o-phthalonitrile or its derivative,1,3-diiminoisoindoline or its derivative and titanium tetra-butoxide ortitanium tetrachloride above a predetermined temperature in the presenceof urea to prepare the titanyl phthalocyanin crystal.

Accordingly, it is expected that the electrophotographic photoconductorusing the titanyl phthalocyanin crystal thus prepared not only improveselectric characteristics and image characteristics in various imageforming devices such as copy machine and printer, etc., but also furthermakes a considerable contribution to economical effects.

1. A titanyl phthalocyanin crystal having the maximum peak at a Braggangle 2θ±0.2°=27.2° in a CuKα characteristic X-ray diffraction spectrumand one peak within the range of 270 to 400° C. other than a peakaccompanied by the vaporization of adsorbed water in a differentialscanning calorimetric analysis.
 2. The titanyl phthalocyanin crystalaccording to claim 1, wherein the titanyl phthalocyanin crystal has nopeak at a Bragg angle 2θ±0.2°=26.2° in the CuKα characteristic X-raydiffraction spectrum.
 3. The titanyl phthalocyanin crystal according toclaim 1, wherein the titanyl phthalocyanin crystal recovered after beingimmersing for 7 days in an organic solvent has at least the maximum peakat a Bragg angle 2°±0.2°=27.2° and no peak at 26.2° in the CuKαcharacteristic X-ray diffraction spectrum.
 4. The titanyl phthalocyanincrystal according to claim 3, wherein a organic solvent is at least oneselected from the group consisting of tetrahydrofuran, dichloromethane,toluene, 1,4-dioxane and 1-methoxy-2-propanol.
 5. The titanylphthalocyanin crystal according to claim 1, wherein the structure oftitanyl phthalocyanin compounds is represented by the following generalformula (1).

(In the general formula (1), X¹ to X⁴ are the same or differentsubstituents, each independently represents a hydrogen atom, a halogenatom, a substituted or an unsubstituted alkyl group, a substituted or anunsubstituted alkoxy group, a substituted or an unsubstituted cyanogroup or a substituted or an unsubstituted nitro group, respectively,the repeat number “a”, “b”, “c” and “d” represent an integer of 1 to 4,respectively and may be same or different, respectively.)
 6. A methodfor preparing a titanyl phthalocyanin crystal having the maximum peak ata Bragg angle 2θ±0.2°=27.2° in a CuKα characteristic X-ray diffractionspectrum and one peak within the range of 270 to 400° C. other than apeak accompanied by the vaporization of adsorbed water in a differentialscanning calorimetric analysis and comprising the following processes(a) and (b); (a) a process for preparing a titanyl phthalocyanincompound by adding a titanium alkoxide or titanium tetrachloride at avalue within the range of 0.40 to 0.53 mole with respect to 1 mole ofo-phthalonitrile or its derivative or 1,3-diiminoisoindoline or itsderivative and adding a urea compound at a value within the range of 0.1to 0.95 mole with respect to 1 mole of o-phthalonitrile or itsderivative or 1,3-diiminoisoindoline or its derivative to react thecompounds, (b) a process for preparing a titanyl phthalocyanin crystalby performing an acid treatment on the titanyl phthalocyanin compoundprepared in the process (a).
 7. The method for preparing the titanylphthalocyanin crystal according to claim 6, wherein the urea compound isat least one compound selected from the group consisting of urea,thiourea, o-methylisourea sulfate, o-methylisourea carbonate ando-methylisourea hydrochloride.
 8. The method for preparing the titanylphthalocyanin crystal according to claim 6, wherein the reactiontemperature in the process (a) is set to a value of 150° C. or above. 9.The method for preparing the titanyl phthalocyanin crystal according toclaims 6, wherein the process (a) is performed in a nitrogen-containingcompound with a boiling point of 180° C. or above.
 10. Anelectrophotographic photoconductor having a photosensitive layer isprovided on a conductive substrate, wherein the photosensitive layercontains the titanyl phthalocyanin crystal having the maximum peak at aBragg angle 2θ±0.2°=27.2° in the CuKα characteristic X-ray diffractionspectrum and one peak within the range of 270 to 400° C. other than apeak accompanied by the vaporization of adsorbed water in thedifferential scanning calorimetric analysis, within the range of 0.1 to50 part by weight with respect to 100 part by weight of a binder resinforming the photosensitive layer.